DIGITAL LIBRARIES: ARCHAEOLOGY,
AUTOMATION, ETDS, AND ENHANCEMENTS
Edward A. Fox
Digital Library Research Laboratory, Virginia Tech, Blacksburg, VA 24061 USA
Email: fox@vt.edu
ABSTRACTHow can we build digital libraries (DLs) more quickly and better? Our next-generation approach is based on the
5S framework, of Streams, Structures, Spaces, Scenarios, and Societies. In particular, we have developed
metamodels using 5S for several broad classes of DLs. One metamodel is for a ‘minimal DL’ (adopting aminimalist approach, which can be extended to common cases of institutional repositories, such as of electronictheses and dissertations, ETDs). Another is for archaological DLs, initially aimed to support integration of anumber of (ETANA) sites in the Near East, but flexible enough to adapt to other regions as well. Using 5S andthese metamodels, we can semi-automatically specify and generate tailored digital libraries, drawing on a pool ofbasic components, along with suitable enhancements, like multidimensional browsing.

INTRODUCTION
Digital libraries (DLs) (Arms 2000; Fox 1993a; Fox 1993b; Fox et al. 1995; Fox and Lunin 1993; Fox andMarchionini 1998, 2001; Fox and Sornil 1999, 2000; Fox and Urs 2002; Lesk 1997, 2005; Witten and
Bainbridge 2002) have evolved since their emergence in the early 1990s as a new class of advanced andintegrated information system. Already, there are many software solutions available (EPrints.org 2002;
Informedia 2005; MIT 2003; Suleman 2002; Suleman and Fox 2001; Suleman et al. 2003; VTLS 2005; Witten
and Bainbridge 2002; Witten et al. 2000). Building on more than a decade of research and development projects(Chen 2000a, 2000b; Fox 1999b; Griffin 1999; Lesk 1999; Rusch-Feja and Becker 1999), further advances andautomation in the DL domain should have even broader benefit for all types of knowledge management: “Key toachieving productivity gains is reducing the human overhead required to obtain and use information.” (Larsen
and Wactlar 2004). As more and more DLs appear, it is essential that a science unfolds, as has been proposed for
related fields like human-computer interaction and data mining (Carroll 2003; Ramakrishnan and Grama 1999).
Since 1999, we have been working to develop a science of, and theory for, digital libraries, referred to as “5S”
(Table 1), since it relies upon five essential concepts, Streams, Structures, Spaces, Scenarios, and Societies (Fox
1999c). We have used 5S to define the key ideas in the DL field (Gonçalves et al. 2004a), construct anontology (Gonçalves, Watson and Fox 2004b), and describe what it means to have a “high quality” DL(Gonçalves 2004). We have applied 5S to automate the implementation of tailored DLs, that suit the needs ofparticular users and are appropriate for content of interest (Figure 1), using tools like 5SGraph (Zhu 2002; Zhu etal. 2004), 5SLGen (Kelapure 2003), and related logging software (Gonçalves et al. 2002; Gonçalves et al. 2003).
Accordingly, in the next section we summarize key aspects of the 5S framework. The following section
highlights our application of 5S to support education, in particular with regard to work on electronic theses anddissertations (ETDs). Then we show, in the domain of archaeology, how 5S can facilitate handling of complex
challenges faced in the world of information technology, such as automation, quality, and rapid enhancement.
Finally, we conclude this paper, and summarize our findings.

5S FRAMEWORK
Scientific theories rest upon formal definitions of primitive concepts and of essential concepts. As with otherwork in computer science, we employ basic primitives: event, function, grammar, graph, language, relation,
sequence, state, and tuple. Next, since DLs are high-end information systems, a set of essential concepts isneeded to provide adequate coverage and definitional power. After studying the terminology used in hundreds ofpapers in the DL field, we found that five concepts suffice. Accordingly, we employ and define the very different,
but complementary, concepts of Streams, Structures, Spaces, Scenarios, and Societies (Gonçalves et al. 2004a) –and show how they can be applied, individually and in combination, to meet our objectives (Table 1).

Table 1 The 5Ss, with examples and objectives
Ss

ExamplesObjectives

Streams

Text; video; audio; image

Describes properties of DL content such as encoding andlanguage for texts or particular forms of multimedia data

Structures

Collection; catalog; hypertext;
document; metadata

Specifies organizational aspects of the DL content

SpacesMeasure; measurable,
topological, vector, probabilistic

Defines logical and presentational views of the several DL
components

Scenarios

Searching, browsing,recommending

Details the behavior of DL services

Societies

Service managers, learners,
teachers, archaeologists, etc.

Defines managers, responsible for running DL services;
actors, that use the services; and relationships among them

5S
Meta
Model

DL
Expert5SGraphDL
Designer

Practitioner
5SL
DL
Model

Teachercomponent
pool
ODLSearch,
ODLBrowse,
ODLRate,ODLReview,…….

Researcher

5SLGenTailoredDL

Logging Module
XML
Log
Fig.1 5S-related tools and applications, and their use in developing DLs
The first column of Table 1 identifies the Ss. The second column illustrates terms and aspects of DLs that
directly fit into each of the Ss. The third column summarizes the basic intent of each S – but each S also can be
employed in diverse other ways, in more advanced information systems, as well as in particular application
domains. Thus, the Society of users is what most consider essential in basic systems, but authors also are in
demand for pre-print services, and DL experts and designers are needed to develop DLs (Figure 1).
Combinations of Ss are required too; an electronic thesis encoded in XML is a structured stream, while asearching service can be defined using four of the Ss: Stream, Structure, Space, and Scenario.
Building DLs has been more art than science. Using the 5S framework, as shown in Figure 1, a more scientificand automated approach is possible. The raw material for implementation is any pool of components, such as
might be found in the Greenstone (Witten et al. 2002) or OpenDLib (Castelli and Pagano 2002) or Open Digital
Library (Suleman 2002; Suleman and Fox 2002a; Suleman et al. 2003) projects. The challenge is to connect
components (along with suitable “glue” to handle workflow) into a tailored DL, suitable for all types of users(Societies), along with support for monitoring quality, such as a logging module that follows appropriate
standards (Gonçalves et al. 2002; Gonçalves et al. 2003). The key players are digital librarians, who function at
various levels, especially as DL experts and DL designers (Figure 1). These players can be more efficient andeffective in helping with the development of DLs if they can work with models instead of code (Shen et al. 2005).
Accordingly we developed 5SL, a language for modeling DLs, that uses XML to describe a DL (Gonçalves andFox 2002; Gonçalves et al. 2001). With the 5SGraph tool (Zhu 2002) a digital librarian can specify a particular
DL by drawing upon a metamodel for that class of DLs. Thus, we see in Figures 2 and 3 metamodels for first a
minimal DL (Gonçalves et al. 2004a), and then for an archaeological DL (Shen et al. 2005). The first metamodel
suffices for any simple DL that is made up of digital objects, supported by basic services (Figure 2). The
second metamodel is suitable for DLs that support archaeology (Figure 3), as is discussed later in this paper.
Streams

Structures

Spaces

Structured
Stream

Structural
Metadata
Specification

Scenarios

Societies

services

Descriptive
Metadata
Specificationindexingbrowsing searching

hypertext
Digital Object

Metadata Catalog

Collection

Repository

Minimal DL

Fig.2 Metamodel for a minimal DL in the 5S framework

Streams

Structures

Structured
StreamDescriptive
Metadata
specificatio

SpacesScenarios

Societies

services

SpaTemOrg
StraDia

ArchObj

Arch Descriptive
Metadata

indexingbrowsing searching
hypertext

ArchDOArch Metadata

ArchColl
ArchDColl

ArchD

Minimal ArchDL

Fig.3 Metamodel for a minimal archaeological DL in the 5S framework

APPLICATIONS TO EDUCATION
One of the first (Fox 1993b), and one of the most important, applications of DLs is to support education (Fox,
Gonçalves and Kipp 2001a). This is a worldwide concern (Kalinichenko 2003), as well as a national priority indiverse nations. In USA, one of the larger initiatives is the National Science Digital Library (NRC 1997; NSDL
2001, 2005; NSF 2005; Zia 2001). There have been well over 150 NSDL-supported projects (NSDL 2005),
including a number in which Virginia Tech has engaged (Fox 2003), the largest being the Computing andInformation Technology Interactive Digital Educational Library (CITIDEL 2002), around which a number of
research investigations have unfolded (CITIDEL 2004; Kampanya et al. 2004; Perugini et al. 2004; Zhang,Gonçalves and Fox 2003). Core support for NSDL, as well as a number of separate funded projects, haveadvanced the overall technological base (Gupta, Ludäscher and Moore 2002; Lagoze et al. 2002). Other DL
initiatives can build upon that base, which we hope also will be a strong support for innovation in education.
DLs can support teachers and learners, K-12 (Tucker et al. 2003) through undergraduate through lifelong
learning, and all disciplines, e.g., Biology (BQCC 2000; NBDL 2001), Mathematics (Krowne 2005; MathForum2000), Physics (Hilf 2000; Maly et al. 2002). Standards (ADL 2005; LTSC 2000; RHA 2001) have facilitated thedevelopment of learning object repositories (WCET 2005). Universities and other types of organizations havebegun organized efforts to build local institutional repositories (Johnson 2002; Lynch 2003) to include andpreserve these and related digital objects, using software like DSpace (MIT 2003). We believe 5S can help.
DLs for education can be modeled by making use of the metamodel given in Figure 2. This suffices when all
resources are digital, when a single site maintains a repository that is based on a collection of digital objects,
when a metadata catalog corresponds to the collection, and when there are at least a set of basic browsing andsearching services (as well as a supporting hypertext structure and an indexing service).
A simple DL for education, supporting graduate education and research, is the Networked Digital Library of
Theses and Dissertations, NDLTD (Fox 1997; Fox et al. 1996; Fox et al. 1997; Suleman et al. 2001a, 2001b). In
discussions dating back to 1999, NDLTD has been described in varying levels of detail using the 5S framework(Fox 1999a, 1999c; Gonçalves 2004). The main Societies involved are graduate students, faculty, university
administrators, and researchers (Fox et al. 2001b; Moxley 2001). Scenarios supported include: uploading
electronic theses and dissertations (ETDs); having them checked and cataloged; harvesting (Suleman and Fox2003) into a union catalog (CALIS 2004; OCLC 2004; Suleman and Fox 2002b; VTLS 2004); and subsequent
search (Luo and Fox 2004) and downloading. (5S) Spaces cover the locations of authors’ institutions and readers,
as well as internal system representations to support searching, and external presentations involved inhuman-computer interaction. Structures include those that support browsing, as well as those associated withmetadata records that conform to suitable standards (Atkins et al. 2001; Dublin-Core-Community 1999; Weibel1999). Streams cover all of the content connected with ETDs, in all media types (Fox, McMillan and Eaton
1999), as well as all the communications among computers, and with users.
However, the 5S metamodel of Figure 2 is inadequate in cases when theses or dissertations only exist as paper or
microforms, whereupon there may not be a digital object, though there typically is a metadata object. Such asituation is part of the expansion needed as we develop richer metamodels, like that shown in Figure 3, tosupport archaeological DLs.

ARCHAEOLOGY AND DLS: ADVANCES AND ENHANCEMENTS
In archaeology, as is shown in Figure 3, there are “real world” objects (ArchObj) that are in collections(ArchColl). This is in addition to corresponding surrogates (e.g., digital images), which are digital objects(ArchDO), and which in turn are part of collections (ArchDColl). The other key addition in Figure 3 is for
spatial-temporal organizations (SpaTemOrg) and stratigraphic diagrams (StraDia), since in archaeology there isan intimate connection between time and space, which must be characterized and represented in order tounderstand the link between an archaeological site and the history of that location.
This connection can be understood in part through work with ETANA-DL (Ravindranathan et al. 2004a;
Ravindranathan et al. 2004b; Ravindranathan et al. 2004c; Shen et al. 2005), a DL developed based on the 5S
approach, to support the field of archaeology, especially building upon work on sites in the Near East. Figure 4
shows one of the screens that comprise the ETANA-DL user interface, demonstrating our approach tomulti-dimensional browsing. We support identification of a subset of the collection based on selection ofparticular periods and sites, thus focusing on key aspects of time and space, but also can deal with otherdimensions, such as that of artifact type. After repeated refinement of the selection, all records can be shown that
fit the chosen constraints, first through a result list that includes thumbnails and metadata, and then in detail.

ETANA-DL has been a testbed to allow us to further develop the 5S approach, to enhance automation, and to
add significant enhancements. Our first prototype was constructed in about 6 months (Ravindranathan 2004),
making use of components from the Open Digital Library initiative (Suleman 2002; Suleman and Fox 2002a).
But since integration of data from a large number of archaeological sites is our aim, we sought additional
assistance from 5S as we worked to automate further the integration of more sites (Raghavan et al. 2005). Figure
5 summarizes the challenge and our approach, which also relates to CITIDEL (Kampanya et al. 2004).
In order to build an integrated “Union DL”, we must consider all of the key aspects of the DLs that are to be
integrated, e.g., DL1 and DL2 as shown in Figure 5. The resulting Union Society is the union of the societies ofeach of the separate DLs. Likewise, we can develop union versions of the key parts of a DL, such as therepository and the catalog. However, the Union Service must include more than the sum of the parts; additional
services are needed to effect the integration (e.g., harvesting and mapping), and to provide help for users tomanage and work with a much larger and more heterogeneous content collection (Raghavan et al. 2005;
Ravindranathan et al. 2004b; Ravindranathan et al. 2004c; Shen et al. 2005).

3 new sites

2 new types of artifacts
Fig.4 ETANA-DL Multi-dimensional browsing
DL1

Union DL

DL2

Union Society
Society☺☺
Archaeologist

Service
Searching☺☺☺☺
Archaeologists
General Public
Union Service
Harvesting, Mapping,
Searching, Browsing,
Clustering, Visualization

Society☺☺
General PublicService
Browsing

Catalog1

Union
CatalogCatalog2

Repository1

Union
Repository

Repository2

Fig.5 Architecture of a union DL

Figures 6 and 7 give details of our approach. We developed Schema Mapper, a tool to map the schema of diverse
DLs into a global schema for a union DL, so that would have a global metadata format and union catalog(Raghavan et al. 2005). Schema Mapper generates a wrapper for each separate DL, so that its contents can bemapped into the union catalog. Figure 7 gives additional detail on our tools and processes for integration.

Virtual Nimrin(VN)

Mapping
VN Metadata
FormatTool
Union ArchDL

VN
Catalog

Halif DigMaster
(HD)

Union
Catalog

Wrapper

GlobalMetadata
FormatHD
Catalog

Wrapper

HD Metadata
FormatMapping

Tool
Fig.6 Union catalog integration

ArchDL5S Archaeology
MetaModel

ArchDL Designer

5SGraphHD Metadata Format

VN Metadata Format
Scenario
Sub-model
ETANA-DL
Union Services
Descriptions

ETANA-DL Metadata Format

VN
Catalog

Wrapper4VN

Wrapper4HD
Inverted Files
SearchService

Index

Union
Catalog

Browse DB
Index

BrowseService

Services DB

Other
XOAI
ETANA-DL
Services

Component
Pool
Browsing
…

5SGen

XOAI

Web Interface

Harvesting
Mapping
Searching
Browsing…

HD
Catalog

Mapping Tool

Fig.7 Extended 5S-related tools and applications, and their use in developing archaeological DLs

Figure 7 illustrates our semi-automatic approach, including extended versions under development for 5SGraphand 5SGen, which will integrate with other parts of the work undertaken for ETANA-DL. Figure 8 demonstrates
the user interface for the browse service mentioned in Figure 7, which builds upon prior work on CitiViz(Kampanya et al. 2004). Thus, after the Nimrin site has been selected, and a list of periods of interest identified(see the lower right portion of the hyperbolic visualization that is given in the upper right of the figure, and theeight rows shown as yellow in the upper left table), for each of four selected types of animal bones (see last rows
in that table), percentages of each bone type (colored parts of each histogram element) for each period (i.e., eachof the eight columns) are shown in the lower right (Shen et al. 2005). Our aim is to semi-automatically generate
the software for such DL services, like those shown in Figures 4 and 8.

Fig.8 Multidimensional browsing: percentages of animal bones across Nimrin cultural phases

CONCLUSIONS
5S has been shown beneficial with regard to the advancement of the DL field toward becoming a science. It
has been applied to describe simple DLs, to support work with ETDs, and to be helpful in the field ofarchaeology. 5S has helped with automation, as is needed to speed up and facilitate the development of digital
libraries. 5S has made it easier to work on enhancements to digital libraries, such as multidimensional browsing,Future work in the DL field can build upon the 5S framework. The theoretical framework for DLs can beextended and its scope expanded to other types of information systems. Difficult problems like interoperability
and quality improvement can be solved, starting at the conceptual level. Practical solutions can be developed,
such as those continuing to unfold at the prototype level with regard to our ETANA-DL efforts. We hope that the
5S framework will be considered by others, and will help them in their DL-related activities.

ACKNOWLEDGEMENTS
Support for the work discussed was provided by the US National Science Foundation (NSF), through grants
DUE-0086227, 0121679, 0121741, 0136690, 0333531, and 0435059, as well as IIS-0307867 and 0325579.
Additional support has been provided by AOL, IMLS, OCLC, and VTLS. Thanks also go to those working on
related projects, especially including ETANA and NDLTD. Particular thanks go to members of the Digital
Library Research Laboratory, Department of Computer Science, and Information Technology at Virginia Tech.

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